Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/16/18
Area Forecast Discussion
National Weather Service Amarillo TX
602 PM CDT Sun Jul 15 2018
00Z TAF Cycle
Showers and thunderstorms will impact the three TAF sites through
about 01Z to 04Z Monday with thunderstorm wind gusts up to 35 to
45 knots and some possible MVFR ceilings and visibilities.
Otherwise, VFR conditions will prevail at the three TAF sites
through 00Z Tuesday. Southeast to south and southwest winds mainly
5 to 15 knots except in and near any thunderstorms where variable
winds sustained at 15 to 25 knots with the higher gusts can be
.PREV DISCUSSION... /Issued 330 PM CDT Sun Jul 15 2018/
Short Term (This Afternoon and Tonight)...
Mid-Upr level trough axis has drifted west through the day and this
has helped improve moisture profiles and seems to have lifted the
lid a bit as we are seeing much more convective development than
this time yesterday. Much of the area is include in SCT POP cats for
the remainder of the aftn into evening with highest coverage
expected along SW to NE diagonal through middle of CWA and across
the OK Panhandle. The HRRR and TTU WRF seem to have good handle on
this now, but CAMs have been struggling to say the least. ML cape
of 1000-2000 J/kg and SB cape of 2000-3000 J/kg and weak shear
supports strong pulse storms. Very isolated severe wind gusts
cause by microburst are possible given 1200-1600 J/kg downdraft
capes noted in SPC meso analysis. That said, lighting and
torrential downpours and localized flooding are likely the main
threat with these slow movers. Expect lingering elevated storms
beyond midnight as we have seen the last several days perhaps
focused on central counties. In fact this is the first time CAMs
(HRRR in this case) seem to even be trying to forecast these. Will
maintain POP through the night as a result. NBM has been doing
well on lows and looks good.
Long Term (Monday through Saturday)...
Continued chances for convection will prevail across the
Panhandles through Monday and Monday night. The forecast area will
remain between one upper high over the Great Basin region and Four
Corners region and the other upper high over the northwest Gulf
states. The upper high over the northwest Gulf states expected to
build back to the west and north across the Panhandles Tuesday.
Convection chances Tuesday afternoon and Tuesday night should be
confined mainly to the far northern portions of the forecast area,
however confidence low. The upper high will build over the
Panhandles mid to late week which will result in hot and dry
conditions Wednesday through Friday and possibly into the upcoming
weekend. A Heat Advisory may be likely over mainly the southern
portions of the Texas Panhandles, especially the Palo Duro Canyon,
Wednesday through Friday as max temps forecast to reach 105 to
108 degrees. A weak shortwave may possibly affect the far northern
Panhandles Friday night which could result in isolated convection,
but again, confidence low. Otherwise, the hot and dry conditions
will prevail the end of the week through the upcoming weekend.
Area Forecast Discussion
National Weather Service State College PA
1101 PM EDT Sun Jul 15 2018
Very warm and humid weather will persist into Tuesday with
a gradual increase in the chance for showers and thunderstorms
until a cold front passes through late Monday night and Tuesday.
Canadian high pressure will follow and bring a refreshing
change back to much lower humidity and near to slightly below
normal temperatures for the second half of next week.
.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
No significant changes to gridded fields that highlight the
overall fair and muggy conditions overnight.
Upper level ridge cresting right over the region late tonight,
coupled with a lack of any appreciable llvl moisture convergence
means a partly cloudy and muggy night for the entire CWA.
Min temps early Monday - ranging from the mid to upper 60s
across the northern mountains and upper 60s to lower 70s
elsewhere, will be 5-10F above normal for mid July.
Aside from a lone shower over the NE corner of Sullivan County,
the regional radar Dual-Pol scope was PPINE.
Last few runs of the HRRR and RAP13 indicate little or no chc
for additional showers overnight, and all of our POPs through
12Z are 10 percent or less.
Patchy 1-2SM fog will form throughout the valleys considering
the high sfc dewpoints and fairly narrow T/Td spread already.
.SHORT TERM /8 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
As the upper trough over OH/KY slides in Monday, it will aid
storms to form, perhaps before noon in the west. WPC MRGL risk
of excessive rain is drawn over the western part of the area
Mon, and we will continue to mention heavy rain poss there. They
should be moving a little from W-E, but still slowly.
Another big worry is the Heat Index may get near 100 as well
Mon. Have chatted with the neighboring offices and the consensus
is that we will likely stay just under advy criteria - u90s.
Nevertheless, it is going to be another hot and muggy one.
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Cold front will move southeast through the Northwest mountains
early Tuesday morning reaching Harrisburg by late afternoon and
clearing the lower Susq valley by evening. High PWAT air, increasing
deep layer shear (20-30 kt)and the cold front may lead to
strong thunderstorms depending on the amount of sunshine. SPC
has portion of Central PA in a marginal risk for severe.
Drier air and building pressure behind the Cold Front Tuesday
night into Wednesday helps clear things out and drop high
temperatures Wednesday about 5 degrees over Tuesday but humidity
will also be notably more comfortable. High pressure over PA
Wednesday night will slide east off the coast. Flow aloft will
shift from northwest to southwest and surface winds will turn
southeast. GFS hints at a marine layer moving into lower Susq
Thursday night and a return of higher dew points may bring some
patchy morning fog.
Next system approaches late Friday with a low center trying to
form on the coastal front off the Carolinas which moves north to
just of the Delmarva and the main parent low center back over
the Great Lake Region to bring more unsettled weather for the
weekend with the chance of scattered showers and thunderstorms.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Storms remain isolated and most airfield will be rain free this
evening. Visibility should be VFR unless you happen to get
right under a cell. But, after dark, the stabilization and light
wind will likely lead to fog formation, esp in places which
received heavy rain today, and in the valleys of the north where
it may clear out completely.
A minor shortwave trough moves in from the west on Monday and
will flare storms up again, perhaps in the morning over the
west. But, the rest of the area will wait until at least noon to
see things flare up. Will just mention some SHRA in the western
terminals aft 14Z, and leave it out of others.
More widespread activity on Tuesday, ahead of a cold front.
Improving conditions after that, as drier air works into the
Tue...CFROPA with numerous TSRA and lowered vis/cigs likely.
Wed-Fri...AM valley fog N, otherwise, no sig wx expected.
Area Forecast Discussion
National Weather Service Quad Cities IA IL
951 PM CDT Sun Jul 15 2018
Issued at 941 PM CDT Sun Jul 15 2018
Area radars show a thin line of convection has developed since 01z
from northeast Iowa into central Iowa, or roughly from northeast
of KDEH, to KIFA, to near KDSM.
Convection appears to be developing mainly due to the strong
theta e gradient in the area associated with what appears to be a
weak trof/front. RAP trends slowly moves this feature east
overnight through the area. However, the RAP does show weakening
convergence over the northwest quarter of the area through 07z
before strengthening it again in the hours prior to sunrise.
Thus will update the forecast to reflect the potential for a
narrow band of mainly isolated to scattered showers moving through
the area late tonight. One cannot rule out an isolated rumble of
An updated forecast should be available in about 5 minutes or so.
Issued at 220 PM CDT Sun Jul 15 2018
Low clouds continued to decrease in coverage during the early
afternoon hours. Scattered showers developed across parts of
eastern Iowa, in an environment favorable for brief funnel clouds,
which were reported in Benton and Johnson Counties. The cloud
cover kept early afternoon temperatures down in the upper 70s to
mid 80s, but heat index values in the mid 80s to low 90s were
.SHORT TERM...(This Evening through Monday)
ISSUED AT 220 PM CDT Sun Jul 15 2018
The main forecast issue in the short term period is the coverage
of showers and isolated thunderstorms this afternoon and tonight,
as well as the potential for additional funnel clouds.
Funnel reports have coincided with developing showers across
eastern Iowa, from Vinton and Cedar Rapids, through Mt. Pleasant
into far northeast Missouri. The axis of favorable surface
convergence and enhanced stretching potential is expected to move
little through the late afternoon, so this area should continue
to be the prime location for additional funnel clouds. Will
continue to cover with special weather statements. A drier airmass
today means that rainfall should not be excessive, and no severe
weather is expected. CAMS are in general agreement in gradually
shifting isolated showers and storms eastward along a weak front
this evening and overnight. Expect another muggy night with lows
in the upper 60s/low 70s.
The front will exit the area to the east Monday morning, and the
far southeast fringe may have some lingering showers in the
morning. Drier air will move into the northwest counties, while
higher dewpoints linger southeast with afternoon heat index values
in the low 90s.
.LONG TERM...(Monday Night through Sunday)
ISSUED AT 220 PM CDT Sun Jul 15 2018
Monday through Wednesday, The upper air pattern aloft will shift to
the northwest as a long wave ridge builds over the inter-mountain
west and a deep trough develops over the eastern CONUS. This flow
will usher in drier air as high pressure builds into the upper
midwest from Canada. Dry and seasonably mild conditions are on tap
for Tuesday and Wednesday with high temperatures ranging in the
upper 70s to low 80s. On Tuesday and Wednesday night, clear skies,
light winds, and dewpoints in the upper 50s to around 60 will
produce temperatures in the lower 60s over most of the region. Lows
in the upper 50s are possible in locations across the north.
Thursday and Friday, The blended models prog a strong upper level
shortwave to push through the western ridge. This wave is expected
to dive southeast over the upper Mississippi Valley, eventually
closing off over the Great Lakes bringing a chance of storms. High
temperatures both days will be in the upper 70s to lower 80s.
Saturday and Sunday, Skies will be mainly dry on Saturday as high
pressure builds into the area out of Canada. However on Sunday, a
cyclonic flow aloft around the back side of the closed low over the
Great Lakes, will bring a chance of storms. Temperatures will be
near to below normal with highs in the 80s.
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 634 PM CDT Sun Jul 15 2018
Diurnal convection and clouds will dissipate through 01z/16
leaving VFR conditions through 06z/16. After 06z/16 MVFR/VFR
conditions with patchy fog are expected. The fog may get locally
thicker and produce patchy IFR condition. After 14z/16 any
IFR/MVFR conditions will improve to VFR.
SHORT TERM...RP Kinney
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
331 PM MDT Sun Jul 15 2018
An active monsoon pattern will continue to produce scattered
showers and thunderstorms this afternoon and evening, with another
round expected on Monday. However, drier air will work into the
region on Tuesday. After Tuesday, weather will become more June-
like with isolated thunderstorms mainly in the Sacramento
Mountains and Gila Region, and high temperatures increasing into
the lower-100s in the lowlands.
Larger scale pattern has evolved as expected, with our split
subtropical ridge still in place (though both the western and
eastern centers are weakening), with a weak trough in between
extending from the Texas Panhandle into south-central New Mexico.
The inverted trough discussed yesterday has wound itself up over
south Texas. While it is most readily apparent at 200 mb, there is
a weak 500 mb reflection as well.
An outflow boundary from Arizona that pushed into SW New Mexico
around Midday has had disappointing results in terms of generating
new convection in SW New Mexico. RAP analysis has a relative
minimum of CAPE over Luna/Dona Ana Counties, but despite this,
cumulus congestus is "clumping up" in southern Dona Ana and
western El Paso counties. Thick anvil blowoff from earlier
convection in the Sacramento Mountains is spreading into the El
Paso and Las Cruces areas from the northeast. Despite this,
outflow has managed to generate new convection from Orogrande
eastward into the Otero Mesa, though this may be aided by the weak
trough hanging back across the eastern half of New Mexico. It`s a
tough call, but El Paso still has a fair shot of getting decent
storms this afternoon/evening.
We`ll hang on to this same pattern again tomorrow, but the NAM/GFS
now suggest eastern parts of the CWA will be clipped by a weak
vort lobe associated with the approaching inverted trough. Several
of the HREF members pick up on this too, showing a more organized
band of thunderstorms moving up from the SE during the early
But for the most part, this inverted trough will mainly benefit
areas south of the border with precip. Drier continental air aloft
will move in behind it, drying out most of the area beginning
Tuesday and lasting through the week. There will be enough
residual moisture around for isolated storms in the higher terrain
of the Gila and Sacramentos, and maybe a lowland stray, but
activity will be much diminished.
Temperatures will slowly climb through the week, likely reaching
the century mark in the lowlands (including ELP) Wed or Thu.
Recycled moisture will try to work around from the north late in
the week, but warm mid-level temperatures will limit instability.
Moisture remains plentiful with scattered thunderstorms and showers
thru the period for all terminals. Best chances for convection will
be between 00Z and 06Z and again after 18Z. During these periods
look for SCT -TSRA AND +TSRA/WIND VRB15G35KT with CIGS 040-060.
Occasional MVFR ceilings and LCL VSBY 3-5SM AGL will also be
possible with any heavier storms passing directly over individual
terminals. Otherwise expect SCT060-080 SCT-BKN120 BKN-OVC250 to
prevail outside of convective episodes.
Abundant moisture is expected to remain in place through Monday with
decent chances for wetting precipitation for all areas. A drying
trend will begin on Tuesday as deeper moisture is pulled westward
into Arizona and high pressure builds over the state. Circulation
around the high will import drier air into the region and reduce
chances for showers and thunderstorms to a more isolated and
mainly mountain based occurrence for the remainder of the week.
Minimum relative humidity values will drop to the upper teens by the
middle of the week and continue into next weekend. Vent rates will
continue be in the good to very good range. Non-thunderstorm induced
easterly winds will remain light and generally under 10 mph. Wind
gusts from thunderstorms will have speeds of 40 to 50 mph.
.PRELIMINARY POINT TEMPS/POPS...
El Paso 73 91 75 95 / 50 50 20 0
Sierra Blanca 69 89 69 93 / 40 60 20 0
Las Cruces 69 89 69 94 / 50 40 40 0
Alamogordo 69 90 70 93 / 40 40 20 0
Cloudcroft 53 68 52 73 / 40 70 40 10
Truth or Consequences 70 89 71 91 / 40 30 40 0
Silver City 62 81 65 88 / 50 60 50 30
Deming 67 88 67 93 / 40 40 30 0
Lordsburg 66 87 69 93 / 50 30 50 10
West El Paso Metro 72 89 72 93 / 60 50 30 0
Dell City 69 94 68 96 / 40 60 20 0
Fort Hancock 71 92 72 96 / 40 60 20 0
Loma Linda 66 87 67 91 / 60 60 20 0
Fabens 68 90 68 94 / 50 50 20 0
Santa Teresa 71 90 71 94 / 60 50 30 0
White Sands HQ 71 89 72 93 / 60 50 30 0
Jornada Range 67 90 68 94 / 60 40 30 0
Hatch 68 90 69 94 / 40 40 40 0
Columbus 69 88 69 94 / 40 30 30 0
Orogrande 72 91 72 94 / 50 50 20 0
Mayhill 57 77 57 82 / 40 60 40 10
Mescalero 57 77 57 84 / 40 70 40 10
Timberon 56 76 55 79 / 40 70 40 10
Winston 57 81 57 85 / 60 50 50 30
Hillsboro 64 87 64 91 / 50 50 40 20
Spaceport 66 89 66 92 / 40 40 30 0
Lake Roberts 53 80 52 86 / 50 60 60 30
Hurley 61 83 62 87 / 50 50 50 20
Cliff 58 86 61 91 / 40 50 60 20
Mule Creek 62 83 65 90 / 40 60 60 30
Faywood 63 85 63 89 / 40 50 40 20
Animas 67 88 67 94 / 50 40 60 0
Hachita 67 87 67 93 / 50 30 40 0
Antelope Wells 67 86 66 91 / 50 50 60 10
Cloverdale 64 82 63 90 / 50 60 60 20
25-Hardiman / 04-Lundeen
Area Forecast Discussion
National Weather Service Lincoln IL
903 PM CDT Sun Jul 15 2018
Issued at 902 PM CDT Sun Jul 15 2018
Two areas of convection are still in progress at the mid-evening
point, in Knox county and south of I-70. High resolution guidance
is showing that those showers/storms will gradually dissipate,
with a spotty shower or storm still possible the rest of the night
in our far SE and far NW. Otherwise, the majority of central and
SE IL should remain dry the rest of the night.
Surface dewpoints in the low 70s overnight will set the stage for
the potential development of fog, some locally dense, as low temps
drop into the low 70s. A stratus layer could also develop in some
southern counties, per the latest HRRR. Have continued with the
increasing cloud trend after 3 am tonight, with patchy fog in all
areas. Precip chances tomorrow look to be mainly in the eastern
half of the CWA, as the cold front passes through the area between
9 am and 2 pm. No severe storms are expected, but locally heavy
rainfall and gusty winds will be possible.
Outside of any storms, winds will generally be light and variable
overnight, and light southerly ahead of the front tomorrow. A wind
shift to NW will follow the front, as less humid air begins to
make an entrance later tomorrow and tomorrow night.
Updates tonight were done to the weather/PoP grids. The remainder
of the forecast looked on track. Updated info should already be
.SHORT TERM...(This evening through Monday)
ISSUED AT 309 PM CDT Sun Jul 15 2018
Majority of the precip was shunted off to the south throughout the
day, with plenty of cu developing early across Central IL. Enough
clouds developed across the region to limit some of the heating.
Satellite imagery also shows a significant swath of dry air, also
evident in the 12z ILX sounding, spread across the region slowly
progressing into the Ohio River Valley. However, the dry air is
not mixing all the way down to the surface through the clouds.
Dewpoints this evening are still in the 70s. And although there
are a few showers scattered about Central IL this afternoon, the
clouds are diminishing in other locations, hinting to a bit of
clearing going into the overnight hours. With the dewpoints that
high, and a potential partly/mostly clear night, patchy fog
concerns come into question. Although a frontal boundary is on
approach, it is moving into a very weak pressure gradient, and
the winds are expected to be light and variable if not calm.
So...along with low pops in the overnight, increasing to
morning... have gone ahead and put the patchy fog in as well. The
struggle between some isolated showers and patchy fog with any
brief clearing will continue through the overnight hours into the
early morning. Winds should start coming around to more
northwesterly in the early morning, but the dry air lags behind
the boundary considerably. Tomorrow will still be rather warm and
muggy as the precip associated with the frontal passage slowly
works across the area. Storms tomorrow will likely be accompanied
by some fairly gusty winds considering the dry air available
.LONG TERM...(Monday night through Sunday)
ISSUED AT 309 PM CDT Sun Jul 15 2018
Once the front moves through, the temps cool into the mid 80s
into the middle of the week, with drier air making it feel
considerably more comfortable. Thursday, the next system deepens
enough aloft to pull even cooler air into the mid levels from the
northeast, potentially setting up some decent lapse rates for
showers and thunderstorms for Thursday night/Friday...and offer
some below normal temperatures going into the weekend. And in the
last 24 hours, the models have corrected that dry weekend in more
northwesterly flow. Currently the GFS and the ECMWF are cutting
off that upper low in the Ohio River Valley, leaving cyclonic flow
in place and slowly drifting over the region for a cloudy and
periodically rainy weekend.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 705 PM CDT Sun Jul 15 2018
A residual surface boundary in east-central IL has been a focus
for a few showers/storms late this afternoon, between CMI and DEC.
The CMI complex has dissipated to light showers, while the
southern end of the convergence line has activated just NE of DEC.
HRRR output is showing the convection may to linger in EC IL this
evening, but coverage should remain isolated.
Lingering boundary layer moisture may cause more IFR clouds later
tonight, esp near DEC, BMI, and CMI, per the HRRR. Have kept the
tempos for IFR fog later tonight, but some of the fog could become
dense. Will watch trends in the high res models to see if LIFR or
VLIFR conditions need to be included in a tempo for late tonight.
Any lingering MVFR clouds early this TAF period should dissipate
with loss of turbulent mixing, so VFR conditions should prevail
until after midnight when fog begins to form.
Winds will be variable across the area, under the weak pressure
gradient, and eventually prevail out of the NW after the cold
front moves through tomorrow. Spotty convection will accompany the
front, but did not include storm chances at any TAF site during
the day tomorrow yet.
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1045 PM EDT Sun Jul 15 2018
Issued at 1045 PM EDT SUN JUL 15 2018
Updated zones to remove last of the thunder earlier and to remove
showers for most areas through the night as shower activity has
diminished to only a few remote showers in Harlan county. This
activity should follow suit and diminish as there will be little
forcing to sustain activity overnight. Latest hi-res model
guidance suggest rain chances tomorrow may hold off until at least
the afternoon hours, so did pull back rain chances a bit during
the morning hours.
UPDATE Issued at 858 PM EDT SUN JUL 15 2018
A few widely isolated showers and storms continue to impact areas
of east Kentucky. However, the trend has definitely been for less
activity as we have moved past sunset. With instability limited
overnight, will pull the mention of thunder from the overnight
portion of the forecast. Will maintain isolated showers
overnight, but most locations will stay dry through the overnight
hours. Withe expected cloud cover overnight, fog will be more
limited tonight, so will not include in the valleys.
.SHORT TERM...(This evening through Monday night)
Issued at 450 PM EDT SUN JUL 15 2018
19z sfc analysis shows low pressure off to the northwest along
with a frontal boundary. This front`s slow approach (along
with some energy aloft) is helping to spread showers and
thunderstorms across Kentucky this afternoon with isolated to
scattered coverage over the JKL CWA. Any of the stronger storms
would contain heavy downpours and plenty of cloud to ground
lightning. The convection is providing some relief from the warm
temperatures this afternoon with readings down in the mid 70s in
the rain and in the mid to upper 80s elsewhere. Dewpoints,
meanwhile, remain elevated in the low to mid 70s while winds,
outside of the storms are running from the south to southwest at
10 kts or less - though blowing at up to 30 kts with any
The models are in good agreement aloft with the start of a
significant pattern change through the short term portion of the
forecast. They all depict the retreat of the ridge that has
dominated our weather for much of the summer so far. This occurs
as a weakening trough passes by to the north and its energy shifts
through Kentucky tonight into Monday. A larger trough will then
move just into the northern Great Lakes sending more height falls
into the Ohio Valley by 12z Tuesday. Given the model agreement
will again favor a general blend though with emphasis on the
higher resolution CAMs and NAM12 for weather details.
Sensible weather will feature evening showers and storms with a
diurnally typical downturn after sunset, though the latest HRRR
seems to suggest the convection lasting deep into the night -
but still rather scattered. Due to the clouds and convection
around will limit the ridge to valley temperature differences
tonight and Monday night. Likewise have kept the fog mainly in the
river valleys, though places that manage to clear out after
seeing rain will also have a shot at some fog in the middle of the
night. For Monday, the front settles closer and with high PW air
in place expect better coverage of the convection along with heavy
rains from individual cells that could become excessive for any
location that receives training storms. Have highlighted this
threat in the HWO - and it corresponds with a marginal outlook
for excessive rains from WPC. Temperatures will still be able to
get quite warm on Monday, but with the clouds and rains around
readings should top out about a category lower than today most
places - though dewpoints remain quite high.
Again used the CONSShort and ShortBlend as the starting point for
the grids with only small adjustments to temperatures based on
terrain tonight and Monday night. As for PoP, basically kept the
blended solution through the short term period while smoothing
out some of the gradients due to uncertainty in this moist and
.LONG TERM...(Tuesday through Sunday)
Issued at 340 PM EDT SUN JUL 15 2018
As the period starts, a southeastward moving cold front will be over
or just northwest of the JKL forecast area, supported by an upper
level trough moving east southeast over the Great Lakes. Warm and
humid air ahead of the front should support at least scattered
showers and thunderstorms.
There is some variation in frontal timing in the models, with an
average suggesting the front will be passed by Tuesday evening.
Behind the cold front, surface high pressure will move from the
Great Lakes across New England Tuesday night through Thursday night
and bring us a return of dry weather. The air mass which arrives
looks like it will be dry enough to allow the colder valleys to dip
into the 50s for lows.
With the high moving away to the east, a return flow of warmer and
more humid air will occur to end the week. At the same time, another
more significant upper trough is forecast to develop and move
southeast over the eastern CONUS. This results in another cold front
and the potential for more showers and thunderstorms. At this long
time range, the models differ in the details for the amplitude of
the upper trough and timing of the surface front. However, both the
ECMWF and GFS are consistent with the same general pattern, lending
confidence for the scenario. The persistence and strength of the
slow moving upper trough supports an extended potential for precip,
probably even after cold fropa.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 858 PM EDT SUN JUL 15 2018
Generally speaking most places should see VFR conditions through
Monday morning. Some fog from the rainfall this evening will be
possible before it lifts in a few hours. More showers and storms
will develop Monday afternoon and evening associated with a cold
front moving in from the northwest. Thunderstorms will cause some
temporary reductions in visibilities and ceilings during the
afternoon hours and will maintain a VCTS in the TAFS. Winds will
continue to be light through the period.
Area Forecast Discussion
National Weather Service Memphis TN
917 PM CDT Sun Jul 15 2018
.DISCUSSION...A combination of a Mesoscale Convective Vortex
(MCV) and ample instability was responsible for the scattered to
numerous showers and thunderstorms earlier during the
afternoon/early evening hours. Showers and thunderstorm coverage
has diminished substantially over the past hour across the Mid-
South. Short term models including many Convective Allowing Model
(CAM) solutions are still running well behind on the evolution of
the earlier convection. Consequently, I`m leaning towards the
latest HRRR at this point for the remainder of the night. Will
make some adjustments to rain chances for the remainder of the
night and to adjust any other elements as needed.
.PREV DISCUSSION... /issued 630 PM CDT Sun Jul 15 2018/
See the 00z aviation discussion.
PREV DISCUSSION... /issued 213 PM CDT Sun Jul 15 2018/
Soaring heat is in full swing across the Midsouth this
hour...with portions of northwest Tennessee reaching criteria then
cooling off quickly from line of storms. Reluctant to cancel the
advisory though as plenty of afternoon is left for them to rebound
back. Out in the western counties untouched by thicker clouds
and/or storms..a few locations have topped 110F.
With regards to convection a few cells have reached near severe
limits off radar...but with no reports of damage or hail. Rainfall
from Lake to Henry counties has been a welcomed 1 to 2.5 inches.
For tonight through Tuesday...short term CAM`s suggesting
multiple rounds of convection over the next 24 to 36 hours.
Current and overnight activity influenced by the passing MCV in
the Lower Ohio Valley...and then tomorrow and Tuesday influenced
by a descending cold front seen in the Plains. Both features
likely to bring a threat for a few strong or severe storms as
dewpoints remain rich over the region...75F+. Concerns for
additional heat related products will now become very
questionable as extensive cloud cover from activity will play a
big role in temperatures. Highs appear to reach 90 to 94F
tomorrow...which could allow an hour or two of 105F heat indices
along and west of the Mississippi River...but widespread values
seen today aren`t favored. With that in mind will allow the
current advisory to expire at 9pm tonight...with the night crew
making a final call on whether areas will need one tomorrow.
Tuesday will be FROPA day...fingers crossed...with slightly better
coverage of storms over the southern two-thirds of the CWA. Heat
indices are forecast to stay below 105F area wide.
Wednesday and Thursday...post frontal airmass will provide some
relief...with highs expected to be at seasonal normals or a couple
degrees below. Dewpoints will fall a good five degrees as
well...ranging from 67F to 72F. Heat indices will generally be in
the 95-100F range. Convection coverage will become more isolated
and mainly during the afternoon hours across the western
counties Wednesday...overspreading the remaining Midsouth
counties on Thursday. Lows will range from the upper 60`s to low
70`s...cooler than what has been seen at MEM for over two weeks.
Next weekend...Rain chances will ramp back up in the long-range
as both the Euro and GFS show an increase flow from the northwest.
In fact, 500mb wind speeds could reach 50kts over the far
northern counties...a late May and June scenario. Coupled with
dewpoints near 70F...passing shortwaves could generate better
storm organization. High and low temperatures this period will
stay close to normal...generally low 90s and low to mid 70s.
Afternoon heat indices for now remaining 95-102 degrees.
Scattered convection will continue much of the evening but should
gradually diminish in coverage. Maintained VCTS at all terminals
for the next several hours. VFR conditions anticipated outside of
convection in most areas, although patchy fog is possible at KMKL.
Expect another round of scattered showers and thunderstorms Monday
afternoon. The best chance for thunderstorms looks to be
along/south of I-40.
Area Forecast Discussion...UPDATED
National Weather Service Nashville TN
924 PM CDT Sun Jul 15 2018
FOR EVENING DISCUSSION.
Fairly quiet evening so far across Middle Tennessee as most of the
convection has either died off or remained well west of the area.
Current thinking is that this trend will likely continue
overnight into the morning hours before another round of
thunderstorms develops Monday mid day/afternoon. Even though
confidence in the HRRR and the other short range models are well
below low normal, do not see anything upstream that would spark
thunderstorms like what we saw this time last night. So with that
said, lowered POPs for overnight but will continue watching area
radars for any hint of something that might produce a spark for
convection. Otherwise, current temperatures are already in the
low to mid 70s so only adjusted based on current trends.
00Z TAF DISCUSSION.
Convection has decreased across the area this evening so expect
VFR Conditions to continue until BR develops bringing MVFR
visibilities to KCKV, KCSV, and KMQY between 08Z-13Z. Another
round of convection can be expected some time after 12Z although
pinpointing the timing will continue to be the main challenge. So
included VCTS after 18Z for TAF terminals until confidence in
development and timing increases.
Area Forecast Discussion
National Weather Service Blacksburg VA
1114 PM EDT Sun Jul 15 2018
High pressure along the Mid-Atlantic coast will move east out into
the Atlantic ocean tonight into Monday. A cold front Will approach
our region Monday and move through Tuesday.
.NEAR TERM /THROUGH MONDAY/...
As of 1110 PM EDT Sunday...
Convection continues to weaken and diminish over our forecast
area. Exception is in the NC High Country where mesoanalysis
shows deeper moisture convergence along the NC/TN border, all
the while a weak upper vort moves southeast from the Cumberland
Plateau toward the southern Appalachians. Should still see
showers fade after midnight, though will keep at least isolated
threat in for a few more hours in the mountains.
Plenty of mid and high clouds around so kept skies cloudier.
This may limit fog formation as well, except in some of the
deeper valleys in the mountains, and rainier spots from
Previous discussion from early evening...
Overall main area of convection still resides along the
Alleghanys south into the NC/TN mountains ahead of weak vort.
Best SBCAPE also resides here, however, seeing weakening trends
as we head toward sunset. Will allow for pops to lower through
this evening in the west. Otherwise expect some fog to form late
tonight where it rained and where less cloud cover resides.
Previous discussion from early afternoon...
An upper level disturbance, weak shortwave trough will move east
across our region this afternoon into tonight. The associated
vertical motion combining with the increasing instability and
moisture around the western periphery of the coastal high pressure
is producing scattered showers and thunderstorms this afternoon. SPC
Mesoscale analysis at 18z showed that CAPEs have climb to 1 to 3k
j/kg and lis are minus 1 to minus 3 in western portions of forecast
area. Mesoscale models like the HRRR and HighresW-arw are placing
the greatest coverage generally west of the Blue Ridge. Some of the
storm may try to drift east into the foothill this evening as hinted
at by NAM and ECMWF. In any case, Scattered showers and
thunderstorms will diminish and dissipate this evening into tonight
with the loss of solar heating. Areas of low clouds and fog are
expected tonight into Monday morning. Under variable cloudiness, low
temperatures tonight will range from the lower 60s in the west to
the lower 70s in the east.
Several upper level disturbances traverses over our area Monday.
The southwest to west flow will combine with rich moisture and
instability to create scattered showers and thunderstorms especially
during the afternoon and evening hours. The best opportunity for
thunderstorms will occur in the mountains. With PWATS climbing to
around 2 inches, some of the thunderstorms have the potential to
produce locally heavy rains. high temperatures on Monday will vary
from the mid 70s in the mountains to round 90 degrees in the
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 240 PM EDT Sunday...
An weak upper level trough will pivot over the region ahead of a
cold front Monday night. A short wave associated with this trough
will keep convection ongoing overnight, but areal coverage of storms
will wane with lose of heating. Convection Monday afternoon and
night will help remove instabilities across the mountains and
therefore limit the potential for strong to severe storms Tuesday as
a cold front tracks over the region. Tuesday morning, the cold front
will move across the mountains, possibly making it to the Blue Ridge
by noon. In the afternoon, diurnal heating along with a lee trough
will generate a line of thunderstorms east of the Blue Ridge. The
surface front is then expected to jump to the lee trough through the
afternoon, continuing to track east during the evening. Models have
this lee trough somewhere between HWY 29 and I-85. It is this area
where strong to severe storms are likely Tuesday afternoon and
Even though the area has been in a dry spell for a week, some
longer, with creeks and streams running well below normal, flash
flooding is still a possibility. With a deep warm layer and PWAT
values well above normal, slow moving strong thunderstorms could
produce localized flash flooding. The mountains are susceptible to
flooding Monday afternoon and evening, while the foothills and
piedmont will see the threat Tuesday afternoon and evening.
The front will be east of I-85 by midnight, however the
dewpoint/Theta-E front lags behind. A few light showers may persist
across northern North Carolina in the evening, but drier air and
clearing skies will works it way south by sunrise Wednesday. There
will be a noticable drop in humidities Wednesday, however, dry air
and abundant sunshine will keep temperatures warm and near normal.
The cooler air will arrive Wednesday night.
Morning clouds and showers will keep mountains temperatures at or
slightly below normal on Tuesday. Temperatures will range from the
mid 70s to mid 80s. Temperatures will be at or above normal for the
foothills and piedmont counties Tuesday. Temperatures will run from
the upper 80s to lower 90s. Following the passing of the cold front,
temperatures Wednesday will fall short of normal by 3F-6F. Highs
will range in the 70s west to 80s east.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 240 PM EDT Sunday...
Dry high pressure will move over New England and wedge south into
Georgia Thursday into Friday. A disturbance will track along the
eastern edge of the wedge (Southeastern states) Friday then off the
North Carolina coast Friday night. At this time, this disturbance is
far enough away to not bring any rain to the area. Over the Great
Lakes, a closed low is expected to form. Short waves tracking around
this low may bring showers and thunderstorms to the mountains Friday
and to the entire forecast area next weekend.
Forecast confidence is high through Saturday as both the GFS and ECM
are in agreement. Models separate on Sunday to where the upper low
will track. The GFS moves the low eastward towards Toronto while the
ECM tracks it south into Indiana. Both scenarios will bring showers
and thunderstorms into the region.
Temperatures through the period will be near normal.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
As of 710 PM EDT Sunday...
VFR conditions this evening with isolated/scattered MVFR
cigs/vsbys with showers in the mountains and near ROA. Showers
diminish overnight and will give way to some MVFR to IFR
fog in the mountains.
MVFR/IFR Showers and thunderstorms should become more
widespread in the mountains especially mountains by Monday
Medium confidence in ceilings, visibilities and winds during
the taf period.
Scattered Showers and storms are expected across the region on
Tuesday ahead of an approaching cold front. However confidence
is too low to pinpoint where the showers and thunderstorms may
occur. Also likely to see late night/early morning patchy fog
result in localized sub-VFR in the valleys and where any earlier
rainfall occurred each day through Tuesday. Conditions will dry
out Wednesday, then moisture will return from the south
Thursday. Scattered storms are expected in the west on Friday.
Area Forecast Discussion
National Weather Service Shreveport LA
1104 PM CDT Sun Jul 15 2018
Scattered convection well north of our airspace should remain to
our north through the overnight hours. Thin cirrus noted on latest
IR Imagery will continue to spread slowly westward through the
overnight hours, otherwise VFR conditions should prevail tonight
through much of the day on Monday. Did add VCTS to the TXK/ELD
terminals as the HRRR is now painting some widely scattered
convection north of the I-20 Corridor late on Monday. Otherwise, a
growing cu field will prevail through the daytime hours on Monday.
Light south winds overnight will become southwest near 10kts or
less for Monday.
.PREV DISCUSSION... /issued 934 PM CDT Sun Jul 15 2018/
Still watching some scattered convection just north of our region
this evening. Short term progs not handling this weakness aloft
very well so for the update, have added slight chance pops across
our extreme northern zones. There should be a decreasing trend
with this activity as we go through the night concerning coverage
and intensity however.
Concerning temps, raised temps a degree or two along the I-20
Corridor of NE TX to mimic overnight lows last night. Shaved temps
just a degree or so across our SE most zones. Thin cirrus was
located across our eastern half so made this change in the sky
grids as well.
All other grids are in good shape so no additional changes were
necessary. Update out shortly...13.
.PRELIMINARY POINT TEMPS/POPS...
SHV 78 98 78 100 / 10 10 10 20
MLU 77 96 77 95 / 10 10 20 50
DEQ 74 94 73 98 / 10 30 20 30
TXK 77 95 76 98 / 10 20 20 30
ELD 77 95 75 96 / 10 20 30 40
TYR 78 96 76 100 / 10 10 10 10
GGG 77 97 76 101 / 10 10 10 10
LFK 75 96 75 99 / 10 10 10 10
Area Forecast Discussion
National Weather Service Great Falls MT
901 PM MDT Sun Jul 15 2018
Most of forecast through daybreak tomorrow remains valid.
Increased cloud cover over much of the CWA, especially south of
the Hi-Line, given latest observed trends and 00Z/Mon HRRR
guidance, which matched reality best. Also increased POPs and
adjusted QPF accordingly over far-southwest MT. Here, a few
showers and thunderstorms remain possible through daybreak Monday
due to an approaching disturbance`s warm conveyor belt undergoing
weak isentropic lift amidst appreciable moisture and instability.
An upper level ridge of high pressure will slowly build over the
northern Rockies over the next few days. As a result, expect
warmer temperatures to gradually move into the region. Afternoon
highs are likely to range from the mid 80s to mid 90s across the
entire region through the entire week. Additionally, weak upper
level disturbances will move through Southwest MT, producing
scattered showers and thunderstorms, mainly Monday afternoon
Mainly VFR and westerly flow aloft expected next 30-hours as a high
pressure ridge builds gradually over the area. However, a
disturbance aloft centered offshore far-northern CA at this time
moves northeastward to central ID by 06Z/Tue. Accordingly, isolated
showers and thunderstorms are expected over/near the higher terrain
of southwest and central MT between 16Z/Mon and 06Z/Tue, with the
best potential for this activity spanning Mon afternoon and evening.
Erratic surface wind gusts of 30-50 knots and brief MVFR are
possible in/near any shower or storm.
/ISSUED 507 PM MDT Sun Jul 15 2018/
Today through Tuesday...No significant changes to the current
forecast. An isolated thunderstorm is possible towards daybreak
near the MT/ID border in Southwest MT otherwise an upper level
disturbance will move into Southwest MT on Monday
afternoon/evening. This disturbance will likely produce some
scattered thunderstorms. A strong storm is possible, but coverage
of the stronger storms looks quite low at this time. A few storms
continue on Tuesday, but mainly over the eastern portions of the
region. Expect above normal temperatures through the period.
For Tuesday night through Sunday...overall a very warm period is
expected. Afternoon temperatures could slowly fall back into the
upper 80s by next weekend, but any cooling effects will be
minimal. The chances for showers/storms looks very low at this
time over the later portions of next week, thus pops are generally
less than 10 percent for most areas. Brusda
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 91 60 91 / 0 0 0 10
CTB 50 90 53 92 / 10 0 0 10
HLN 57 87 59 89 / 0 10 10 20
BZN 54 83 56 84 / 0 20 20 40
WEY 49 74 45 76 / 20 30 30 30
DLN 55 82 53 83 / 10 20 30 20
HVR 53 92 60 94 / 0 0 0 20
LWT 55 84 58 83 / 0 0 10 40
Area Forecast Discussion
National Weather Service Tulsa OK
847 PM CDT Sun Jul 15 2018
Main concern is the potential for thunderstorm redevelopment late
tonight and into early Monday morning, mainly across northeast
Oklahoma and possibly northwest Arkansas. The latest mesoanalysis
shows a well defined instability axis stretching roughly west to
east across northeast Oklahoma into west central Arkansas, with
multiple outflow boundaries from the afternoon and early evening
convection also in the same area. This evidence, along with the
last couple of HRRR runs, support the potential for additional
development later tonight as another weak disturbance moves
through the region. Only a few changes have been made to the
thunderstorm chances through tomorrow morning, as the inherited
forecast was already pointing toward this solution. The main
change was to extend the axis of higher thunderstorm chances
farther west, to the edge of the forecast area. No other major
changes were made to the going forecast. Updates already out.
.PREV DISCUSSION... /Issued 637 PM CDT Sun Jul 15 2018/
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Much of the convection that developed this afternoon has since
dissipated across ern OK and nwrn AR. However, numerous outflow
boundaries remain across the area, including one that is moving south
from convection in sern KS, and several across far ern OK and nwrn
AR. Mesoanalyses indicate that CIN has increased across nern OK ahead
of the KS outflow boundary but remainder of area remains unstable
and uncapped. Additional development possible this evening across
nwrn AR, so included VCTS for a few hours those sites. Not as
confident as last night in where and if overnight convection will
redevelop, so no mention of TSRA overnight. Scattered thunderstorms
likely to redevelop Monday afternoon and carried PROB30 groups all
sites with that expectation. VFR conditions all sites through the
forecast period outside of TSRA.
PREV DISCUSSION... /Issued 312 PM CDT Sun Jul 15 2018/
Convective potential over the next several days will be the main
forecast concern. The heat will be another concern thru tomorrow,
with a break expected for a day or two. More excessive heat is
expected toward the latter part of the week.
A weak upper trough axis has become more east-west aligned today,
stretching from Illinois to northwest Oklahoma. To the south of
the trof, an axis of richer deep layer moisture resides over
Oklahoma and northwest Arkansas. For the past couple of mornings,
a persistent band of mid level clouds and thunderstorms have
affected portions of northeast Oklahoma to the south and east of
this feature. The activity today was displaced southeast of where
it was yesterday, and the corresponding band of afternoon
convection near the differential heating zone has also shifted
southeast today compared to yesterday. The latest CAM guidance
suggests that this band of mid level showers and storms will
develop a bit farther southeast again tonight into Monday and have
thus adjusted PoPs to account for this trend. The guidance
suggests scattered afternoon convection could develop across the
region on Monday afternoon. Afternoon heat indices will flirt with
advisory criteria again, however, uncertainties regarding both
the mid level cloud canopy and convection, and expected afternoon
storm coverage could limit the spatial and temporal extent of the
advisory heat. Therefore, will elect to hold off on any headlines
and will let the next shift reevaluate.
NW flow will develop aloft over the Plains as a strong shortwave
trough dives southeast over the Great Lakes and Midwest. A weak
surface front will drop down into the region, setting up for a
favorable window for convective potential across portions of the
region Monday night thru Wednesday. The heat should back off for a
day or two as well.
Mid level heights rise during the latter part of the week. The
latest ECMWF shows a fairly intense low level thermal ridge
extending east across Oklahoma Thursday and Friday ahead of a weak
boundary. Our area could see widespread triple digit heat during
this time frame. Temps may drop some for the weekend, but that
isn`t completely certain this far out. The time period from mid
July to mid August is our hottest time of year on average.
Area Forecast Discussion
National Weather Service Tucson AZ
240 PM MST Sun Jul 15 2018
.SYNOPSIS...Plenty of moisture and instability will remain in
place to support daily showers and thunderstorms through the middle
of this coming work week. A few storms may generate strong winds and
heavy rain. With the storms, temperatures will generally remain
below average. Drier air may spread into the region late in the week
for less thunderstorm activity and warmer daytime temperatures.
.DISCUSSION...After a wet morning across much of southeast Arizona,
the rain was ending with clouds diminishing in coverage late this
afternoon. Showers and thunderstorms have struggled to redevelop in
the Flash Flood Watch area northeast of Tucson. Latest HRRR solution
suggested that the air mass was becoming too stable to support
strong showers or thunderstorms this evening. However, regional
radar continued to detect new thunderstorm development along the Rim
country into the White Mountains. Despite what the HRRR was showing,
will keep the Flash Flood Watch going for now based the possibility
of the current activity moving into the watch area. Otherwise, the
overall pattern will remain favorable for daily shower and
thunderstorm activity. Medium ranges models still hinted at some
drying and warming aloft by the end of this coming work week. If
this materializes, less thunderstorm activity can be anticipated with
high temperatures returning to seasonable readings.
.AVIATION...Valid through 17/06Z.
Cloud bases from 5k-10k ft AGL with BKN-OVC clouds above 20k ft AGL.
Isolated -TSRA/-SHRA, becoming scattered -TSRA/-SHRA after 16/21Z.
Surface winds remain below 12 kts through the period. Aviation
discussion not updated for TAF amendments.
.FIRE WEATHER...Deep moisture continues to reside over the region
allowing for the development of showers and thunderstorms. The
pattern begins to gradually shift by the middle of next week
reducing the probability of precipitation, but isolated storms could
still develop, especially over the higher terrain. Temperatures also
look to warm several degrees above normal. 20-ft winds remain below
15 mph, although the Upper Gila River Valley will experience gustier
northwesterly winds at times.
Flash Flood Watch until 8 PM MST this evening for AZZ505-506-
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